Electrically-wound clock



1930" c. E. DE LQNG EDECTRIGALLY wou'mn cLocK Filed Oct. 4-, 1926 4 4 m J 3 4 M WW N Hwy H3 2 8 w 9L Z w Mm WNW W Ifnfenlon Patented Dec. Id, 193@ CHARLES E. DE LONG, F SPRINGFIELD, ILIINQIQ, ASSIGNOR IQ A'NGAMQ ELECTRIC COMPANY, 015 SPRINGFIELD, ILLINOIS, A CQBFQRA'IION 011" ILLINQI nnno'raIcattv-worrn'n' canon Application filed @ctober 19%. serial No. 1%,293.

The present invention relates to electrically wound clocks, and particularly to clocks of this type wherein the energy for winding the main-spring is derived from a small electrio motor, generally incorporated in the clock.

Heretofore, in clocks of this type, the customary method of controlling the motor, i. c., stopping and starting the same with the winding and unwinding of the clock spring, has

been to open and close the motor circuit, through switch mechanism made responsive to the tension of the main spring, or actuated by the winding and unwinding of the spring through a predetermined number of'turns.

Electrical contacts requiring frequent opening and closing are always subject to pitting, arcing, etc., and hence these prior clocks have not been commercially successful, owing to the imperative necessity of a clock giving reliability of operation over indefinite periods of time, without service or attention.

The fundamental object of the present invention is to obviate the difficulties inherent in the use of electrical contacts by providing an electrically wound clock in which the control exercised over the motor is in the nature of a mechanical braking thereof rather than an opening and closing of the motor circuit.

Small motors of the induction type are now obtainable, which will permit of braking down to a dead stall without injury to the motor and without any objectionable load fluctuation being imposed on the line supply-- ingthe motor. Such motors can be slowed down, stopped and started indefinitely through braking retardation without deterioration of any of the working parts of the clock mechanism or motor.

A further object of the invention is to provide improved braking mechanism which will be sensitive in its action, to the end of keep ing the winding and unwinding limits of the clock spring within a comparatively small range,'whereby an approximately uniform tension is always maintained on the clock spring. The braking control forming the essence of this inventionenables this tcnsional variation of the clock spring to be mainvtained between much closer limits thanv is on the plane of the line 22 of Fig. 1, the

winds the main spring practicable in a clock wherein the motor circuit is opened and closed by contact mechanism. Because of the pitting and deterioration of the contacts in these latter types of electrically wound clocks it is not practicable to open and close the motor circuit with the frequency required to obtain this close regulation of the clock spring tension. Such close regulation of the clock spring tension, as obtained by the present braking control, augments the time keeping accuracy of the clock.

Referring to the accompanying drawing illustrating a preferred embodiment of my invention:

Fig. l is a front or face view of a clock movement embodying the invention, the front mounting late being broken away to illustrate part ot the gear train;

Fig. 2 is a transverse sectional view taken major part of the gear train being omitted from this figure for clarity of illustration;

Fig. 3 is an axial sectional view through the main spring drum and arbor on the section plane 33 of Fig. 2;

Fig. 4 is a fra mentary detail view of the two cooperating raking elements, and

Fig. 5 is a view similar to Fig. 2, illustrating a modification.

The clock movement may be of any preferred design or construction, the present invention being capable of embodiment in practically any type of movement with very little modification of standard construction. As exemplary of a typical construction of clock, I have shown in Figs. 1 and 2 aiesign wherein the gear train, main spring, c., are all mountedin a frame structure comprisin front and rear disc-like plates 8 and 9, held in spaced relation by posts 11. The minute hand (not shown) is carried on a central arbor 12, and the hour hand is supported on a sleeve 13 which is connected to the minute hand arbor through the usual speed reducin gearing 14 as is typical of conventional cloclg The electric motor 15, which is preferably mounted on the outer side of the rear plate 9, the frame of the motor having extending lugs 17 which aresecured to spacing posts 18 by 100 96 practice.

screws 19. This motor is preferably of a small induction type, capable of being connected directly to an ordinary lighting circuit. The armature shaft 21 of the motor extends through the back plate 9 and carries a small pinion 22 which meshes with a relatively large gear 23 on an arbor 24 pivoted between the end plates. The pinion 22 and gear 23 are preferably located in close proximity to the back wall 9, the large gear 23 constituting the rotating element to which the braking retardation is applied, as will hereinafter appear.

The reduced speed of the arbor 24 is transmitted through a pinion 25, mounted on this arbor, to a large gear 26 mounted on a second arbor 27, also journaled in the end plates 8 and 9. A pinion 28 mounted on this second arbor transmits the reduced speed thereof to a large gear 29 mounted on a third arbor 31, also journaled at its ends in the front and rear plates. On this third arbor is a pinion 32 which meshes with a large gear 33 which is pinned to the main spring arbor 34. The second and third arbors 27 and 31, together with their respective gears, have been omitted from Fig. 2 to avoid obscuring the illustration of the braking mechanism. As shown in Fig.3, the main spring 35 and spring barrel 36 are mounted on the main spring arbor 34, preferably adjacent the back plate 9, the spring barrel being freely rotatable on the arbor. Such arbor comprises an enlarged portion 34 which enters the spring barrel through an axial hub 37 extending there- 7 from, the inner end of this enlarged arbor portion 34 having the inner convolution of the main spring 35 secured thereto as by a pin or key 38. The outermost convolution of the main spring is suitably connected to the spring barrel, whereby the tension of the spring operates to rotate the spring barrel and the ring gear 39 extending from the periphery thereof. This ring gear 39 meshes with a pinion 41 mounted on thecentral,minute hand arbor 12. Any suitable escapement mechanism 42 is operatively connectedto the minute hand arbor 12 through a suitable gear train, not shown.

Referring to Fig. 3, the hub 37 which extends forwardly from the spring barrel is internally threaded, as indicated 'at 43 to receive the threaded end of a collar or bushing 44. This collar is provided with diametrically opposite slots 45 extending longitudinally of that portion ofthe collar pro ecting forwardly beyond the end of the threaded hub 37. The ends of a transversely extending pin 46, rigidly secured in the arbor portion 34', project into these slots 45. This connection between the arbor portion 34' and the collar 44 compels the collar to stop and start rotation concurrently with the arbor, but permits the collar t move longitudinally along the arbor. A thrusting flange or collar 47 projects radially from the front end of the shiftable collar 44.

vEmbracing the extending portion of the collar 44 is the forked end 48 of a lever 48 which extends transversely through the various arts of the gear train before de scribed f dr pivotal mounting at 49 on a post 51 extending forwardly from the back wall 9 at a point adjacent the gear 23 and arbor 24. As shown in Fig. 1, the pivotal mounting of the lever 48 on the post 51 is preferably effected by forking this end of the lever to embrace the post and to receive a pivot pin passing through the lever and post. Adjacent its pivoted end the lever. carries an adjustable screw member 53 having a threaded portion 54 screwing through a tapped hole in the lever. The inner end of this screw is adapted to bear against a braking surface 55 rotating with the gear 23. This brakingsurface 55 may be the actual side of the gear, but preferably it consists of a disc of fiber or some similar material'secured to the gear.

In the operation of the clock, the energization of the motor 15 will drive through the gear train previously described, which will operate to impart a slow speed winding rotation to the main spring arbor 34. As this arbor is winding the main spring, it is also revolving the threaded collar 44 within the threaded hub 37 of the spring barrel. With tension existing in the spring 35 the spring barrel will, of course, be rotating in the same direction as thearbor 34, but the rotation of this spring barrel will be so slow compared to the winding rotation of the arbor that it may be considered as practically stationary. Hence the rotation of the threaded collar 44 will result in the collar screwing inwardly into the hub 37, the threads having this direction of lead. As the spring approaches the desired limit of its winding tension, the flange 47 0f the collar 44 approaches and .contacts with the forked end 48 of the lever 48, gradually swinging this lever backwardly. This will bring the end of the screw member 53 against the braking face 55 on the gear 23, exerting a gradual braking retardation thereon, until the motor 15 ceases or substantially ceases rotation at the point where the desired winding tension has been given the spring 35.

With the main spring arbor 34 inert, or substantially inert, as the result of the aforesaid braking action, the continued rotation of the spring barrel 36 will gradually screw the threaded collar 44 out of the end of the threaded hub 37. When the spring barrel has revolved through a given angular distance. corresponding to the lower predetermined limit of its spring tension, the flange 47 will have backed away from the forked end 48 of the lever 48 and will have removed the braking friction of the screw 53 frpm the brake surface 55. Accordingly, the motor 15 will be permitted to resume rotation, with 5, the shifting movement of the braking lever is effected from two screw-threaded elements disposed to one side of the main spring arbor, and operatively connected to this arbor and to the main spring barrel. A countershaft extending parallel to the main spring arbor 34, is indicated at 57, the ends of this countershaft being suitably journaled in the front and rear plates 8 and 9. This counter-shaft carries a threaded portion 58 over which screws a threaded gear 59 which meshes with the gear 33 of the main spring arbor. A gear 61, pinned to the countershaft 57, meshes with the ring gear 39 of the main spring barrel. Extending from one side of the relatively wide threaded gear 59-is a grooved collar 62 which is embraced by the forked end 48 of the braking lever 48. In the operation of this modified embodiment the winding rotation transmitted to the main spring arbor 34 will in turn be transmitted to the relatively wide gear 59. During this winding rotation the gear 61, and hence the threaded portion 58 of the countershaft will remain almost stationary because of the relatively low speed rotation of the spring barrel 36. Hence, the relatively wide gear will screw forwardly along the threaded portion 58 of the countershaft, applying a swinging movement to the braking lever 48 for braking the rotation of the electric motor when the main spring has been Wound through a predetermined angular distance, in the same manner described of the preceding embodiment. Similarly, with the motor 15 inert, or substantially inert, the unwinding of the main spring will slowly revolve the gear 61, and hence the threaded portion 58 of the countershaft, with the result that the wide gear 59 will be moved slowly back from its previous advanced position and will release the braking friction edective on the gear 23 when the main spring has unwound through a predetermined angular ro-' tation.

As evidenced by this latter modification, the relative screw threaded motion for imparting swinging movement to the braking lever canbe obtained by coacting parts disposed at different points, either in the gear train or operatively connected thereto. Similarly, the location at the moving brake surface need not be confined to the gear 23, as this braking effort might be applied to a braking surface carried directly on the armature shaft 21,0r on either of the other arbors 27 and 31. (Certain distinct advantages accrue, however, to locating the screw threaded elements and the braking elements substantially as shown in Figs. 2 and 5. The main spring arbor 34, or the countershaft 57 of Fig. 5, are slowly rotating, high torque elements enabling a slow moving force of large moment to be ap lied to the braking lever. The braking surf ace 55 on the side of the gear 23 revolves at a relatively high speed but with little torque, and hence the braking ell'ort applied thereto controls the rotation of the motor to a nicety. By ap lying the braking retardation to a brake sur ace on the arbor 24 rather than on the armature shaft, the latter is relieved of the end thrust incident to the braking operation.

In the event of the supply of current to the motor being interrupted, the reserve tension of the main spring 35 will be sufficient to continue the operation of the clock for a considerable period of time. As soon as current again comes back on the'line, the motor will rewind the main spring to its previous working tension. By adjusting the screw 53 in its threaded mounting in the lever 48, the upper limit of the working spring tension can be shifted to anydesired point in the total range of spring tension.

What I claim as my invention and desire to secure by Letters Patent, is-

1. In an electrically wound clock, the combination of a clock spring, an electric motor, a gear train operatively connecting said electric motor wit-h said spring, a rotating brake surface associated with said gear train adjacent to the motor end thereof, a pair of threaded members operatively connected to the opposite ends of said spring, brake mechanism responsive to relative threading motion between said members for applying frictional braking pressure to said brake surface, and means for relatively adjusting said brake mechanismand said brake surface.

2. In an electrically wound clock, the combination of a main spring having an arbor and a'spring barrel associated therewith, an electric motor, a gear train operatively connecting said electric motor with said main spring, brake mechanism associated with said gear train adjacent to said electric motor, a threaded boss extending from said spring barrel, a threaded bushing rotating with said main spring arbor and cooperating with said boss, means for transmitting the shifting a movement of said threaded bushing to said brake mechanism, and means for adjusting said brake mechanism whereby said electric motor will be operative to wind said spring to diiterent desired tensions.

llltb 3. lln an electrically wound clock, the comjecent to the motor end thereof, a pair of cooperating screw members, one of which is connected to revolve with seicl arbor and the other of which is connected to revolve with said driven member, one of said screw memoers being caused to shift enolwise by rele- "hive rotation between said members, and a, lever for transmitting the shifting movement of said latter screw member tosaic? brake mechanism.

Cit'LARLES LGNG, 

